Validator
In simple terms
A validator is the proof-of-stake equivalent of a miner. Instead of spending electricity to earn the right to add blocks, it locks up capital that can be taken away if it misbehaves.
Definition
A participant that proposes and attests to blocks on a proof-of-stake network, backed by staked collateral.
In depth
A validator is an identity registered with staked collateral, running client software that proposes blocks when selected and attests to blocks proposed by others. Rewards accrue for correct, timely participation; being offline forfeits rewards, and provable violations such as signing two conflicting blocks trigger slashing, which destroys part of the stake. Selection is pseudo-random and weighted by stake, so influence scales with capital rather than with hardware, which is the core economic difference from proof of work.
How does Validator work?
An operator deposits the required stake and runs a node continuously. The protocol selects proposers and assigns attestation duties each slot. Performing them correctly earns issuance and fees; missing them loses potential rewards; equivocating loses principal. Most holders do not run their own validator, and instead delegate to an operator or use a staking service, which trades direct control for convenience and introduces a counterparty.
An example
Running an Ethereum validator requires an illustrative 32 ETH stake and a machine that stays online. A staking service pools smaller amounts to reach that threshold and takes a percentage of the rewards, so the depositor earns a little less in exchange for not operating anything.
Figures are illustrative only.
What beginners get wrong
- Assuming staking rewards are risk-free yield. Slashing, downtime, operator failure and the volatility of the staked asset are all real.
- Confusing a validator with a node. Every validator runs a node; most nodes are not validators.
- Overlooking exit and unbonding delays. Staked capital is frequently not withdrawable on demand.
Related terms
Part of
How does a blockchain transaction actually work? — the subject page for blockchain mechanics, with all 15 of its definitions in one place.
Educational only — not financial advice.